Type of Document Master's Thesis Author Chassot, Amanda M. URN etd-06112009-155707 Title The Combined Role of ENSO-driven Sea Surface Temperature Variation and Arctic Sea Ice Extent in Defining Climate Conditions in the Southwestern United States Degree Master of Science Department Geosciences Advisory Committee
Advisor Name Title Sewall, Jacob O. Committee Chair Barrett, John E. Committee Member Kraal, Erin R. Committee Member Spotila, James A. Committee Member Keywords
- Arctic sea ice
- Little Ice Age
- climate change
Date of Defense 2009-05-10 Availability unrestricted AbstractPrevious research indicates that future reductions in Arctic sea ice cover (SIC) could alter storm tracks and precipitation patterns in western North America and negatively impact water resources in the American southwest. Other research suggests that multiple periods of increased precipitation and/or cooler temperatures in the American southwest during the Little Ice Age (LIA) were due to strong El Niño events; historical records also describe expanded Arctic SIC at this time.
We use 16th-19th century Arctic SIC records from the ACSYS Historical Ice Chart Archive as a basis for expanding Arctic SIC from 1870 HadISST data to theoretical LIA extents. Then, in a suite of sensitivity studies, we investigate the relative influences of and interactions between El Niño-Southern Oscillation (ENSO) related sea surface temperature (SST) variation and varying Arctic SIC in controlling storm tracks, precipitation patterns, and overall climate conditions in the American southwest.
We find that tropical Pacific SSTs greatly influence climate system response to variability in Arctic SIC, with ENSO-Neutral SSTs permitting the greatest response.
Additionally, the degree of expansion and symmetry of Arctic SIC also influence precipitation regime response. These findings suggest that the climate response to future Arctic SIC retreat may not only be highly dependent on the spatial patterns and extent of SIC reductions, but also upon ENSO variability, such that El Nino events may reduce the potential climate impact of ice reductions as compared to Neutral or La Nina events.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access chassot_thesis3.pdf 21.57 Mb 01:39:52 00:51:21 00:44:56 00:22:28 00:01:55
If you have questions or technical problems, please Contact DLA.